WASHINGTON (CNN) -- A federal watchdog agency is investigating whether one of the U.S. attorneys fired in a Justice Department shakeup was punished for missing work to serve in the Navy Reserve, the ex-prosecutor said Wednesday.

David Iglesias, who was the U.S. attorney for New Mexico until February, told CNN that an official in the Office of Special Counsel approached him shortly before his testimony to Congress about the firings in early March.

Among other duties, the office is charged with protecting the job rights of National Guard and Reserve members, some of whom are called away from employers for long periods of time.

Iglesias was one of eight U.S. attorneys fired in a round of dismissals last December. Though all are political appointees who serve at the pleasure of the president, the Justice Department's initial description of the firings as "performance-related" triggered allegations of improper political influence on pending cases and calls for Attorney General Alberto Gonzales to resign.

Justice later said the appointees had failed to support Bush administration priorities such as immigration enforcement or the death penalty, but admitted one was removed so a former aide to White House political adviser Karl Rove could get the post.

Senators, including some Republicans, have also questioned Gonzales' credibility after his initial explanations for the firings.

Iglesias is a captain in the Navy Reserve and estimated that he spent 40 to 45 days a year on duty, including weekends. He was cited as an "absentee landlord" in a Justice Department document laying out reasons for the lawyers' dismissals.

"That was suspicious in and of itself, because virtually all of my time away from the office has been on official government business -- probably 75 percent military and 25 percent DOJ [Department of Justice]," he said.

The Uniformed Services Employment and Reemployment Rights Act bars employers from taking action against National Guard and Reserve members based on their military service and allows them to reclaim their jobs after periods of active duty or training.

Violating the act is a civil matter with possible remedies including reinstatement -- "which I'm not interested in," Iglesias said -- or back pay.

Iglesias said he was not aware of any complaints about his office attendance before his firing -- "Then all of a sudden I find out there were problems that were never addressed with me," he told CNN.

Iglesias said he has had several conversations about his case with the Office of Special Counsel, and faxed official complaints to the agency on Tuesday.

The Justice Department offered no comment on the controversy Wednesday.

William Moschella, the No. 3 official at the Justice Department, told a House subcommittee in March that Iglesias was fired for delegating too much responsibility to his deputy.

And Gonzales' former chief of staff, Kyle Sampson, told the Senate Judiciary Committee last week that Iglesias was added to the list of lawyers to be fired only after November's congressional elections.

He said Rove had complained that Iglesias had not pursued voter fraud cases aggressively enough.

Iglesias has also said he felt "leaned on" when two Republican members of New Mexico's congressional delegation, Sen. Pete Domenici and Rep. Heather Wilson, called him to inquire about pending corruption cases against state Democrats before the November elections.

He said he can't judge any explanations offered by the Justice Department for his firing, "because the official explanations for our dismissals have changed."

Private meeting rejected

The lawyer for a Justice Department official who has invoked the Fifth Amendment over the firings assailed congressional criticism of her decision Wednesday, comparing it to the abuses of former Sen. Joseph McCarthy.

A spokesman for the House Judiciary Committee called the comparison "bizarre and overheated" and questioned whether the official, Monica Goodling, has legal grounds to take the Fifth.

Goodling, the counselor to Attorney General Alberto Gonzales and the Justice Department's White House liaison, announced last week that she would invoke her constitutional right against self-incrimination rather than answer questions about the firings.

Her lawyer, John Dowd, said Deputy Attorney General Paul McNulty has accused Goodling of misinforming him about the issue before he testified about it earlier this year -- an allegation he said Goodling denies.

Dowd said House and Senate leaders' criticism of Goodling smacked of McCarthy's denunciations of "Fifth Amendment Communists" during the "Red Scare" of the 1950s, and he warned lawmakers against threatening to publicly humiliate his client.

Goodling's decision "can in no way be interpreted to suggest that Ms. Goodling herself participated in any criminal activity," he wrote in a letter to lawmakers investigating the firings.

Dowd wrote that McNulty's account -- that Goodling had helped prepare inaccurate testimony to the Senate Judiciary Committee -- was "sufficient predicate" for her to take the Fifth, "regardless of whether Mr. McNulty's allegation is factually correct -- which it is not."

A Judiciary Committee spokesman, who requested to remain anonymous, said committee members had hoped Goodling would speak privately to them about her refusal to testify.

Meanwhile, a member of the Senate Judiciary Committee said that senators should consider offering Goodling immunity in exchange for testimony about her role in the shakeup.

Sen. Sheldon Whitehouse, a Rhode Island Democrat, told CNN that grants of immunity have hampered past criminal investigations in Washington, but that the option should be considered in this case.

Goodling, the counselor to Gonzales, was among the senior Justice Department officials who participated in meetings and e-mail traffic about the planned dismissals. She went on paid leave as the controversy grew about the federal prosecutors' firings.

Whitehouse and Senate Judiciary Chairman Patrick Leahy have asked Gonzales for suggestions on how to deal with Goodling's decision to take the Fifth.

The Justice Department did not return calls seeking comment Wednesday.

Gonzales is scheduled to appear before the Senate Judiciary Committee on April 17.

His former chief of staff, Kyle Sampson, told senators last week that he began talking about the firings with Gonzales in early 2005 but defended the shakeup, saying nothing was done for improper reasons.